In gas Pressure Reduction Stations, the gas is pre-heated before the pressure is dropped to prevent the formation of hydrates which can cause damage to the pipeline and associated equipment. The typical pressure reduction varies between 400 to 900 PSIG (pounds per square inch gage) for main transmission gas lines to local distribution lines and from 50 to 95 PSIG from local distribution lines to consumers. When gas is depressurised the temperature drops. The rule of thumb is that for every 100 pounds of pressure drop across a pressure reducing valve the gas temperature will drop by 7 F. When the pressure is reduced by the use of an expander, the temperature drop is greater because it produces work. The heat required to prevent formation of hydrates is normally provided by hot water boilers, gas fired line heaters or waste heat from; gas turbines, gas engines or fuel cells. In some stations, due to its large volumetric flows and pressure drops, energy can be and is recovered, by a combination of gas expander and boiler. For a more efficient recovery, combinations of gas expanders with CHP processes (Combined Heat and Power) or CCHP (Combined Cooling Heat and Power) processes are possible. The limitation in these applications are the economics which are driven by flow volumes, pressure delta, seasonal volumetric flows and 24 hour volumetric flows. Because of so many variables that impact on the economics of adding a gas expander be it with: a boiler, CHP or CCHP the current gas pipeline operators choose to pre-heat the gas by the use of boilers and or heaters.